Process for sulphating olefines



Patented July 25, 1933 UNITED STATES Luau:

PATENT oFFica T BENJAMIN 'I'. BROOKS, OF GBEENWIGH, CONNECTICUT, AND EUGENE J. CARDARELLI, OI NEWK, NEW JERSEY, ASSIGNORS, BY MESNE ASSIGNMENTS, -T STANDARD ALCOHOL COMPANY, 01 WILMINGTON, DELAWARE, A CORPORATION 01! DELAWARE No Drawing.

This invention relates to the sulphation of propylene and will be fully understood from the following description:

The propylene to be sulphated may be obtained from any available source as, for example, from the products of destructive distillation of materials containing carbonand hydrogen. It may conveniently lac-obtained by the pyrolysis of shale oil or petroleum, and these oils may be hereinafter generically designated as mineral oils.

Propylene occurring in the gasesproduced b cracking petroleum oil has been commerclally sulphated either by the use of concentrated sulphuric acid at relatively low temperatures or of more dilute sulphpric ac d at or about normal temperatures. in general, elevation of temperature or increase of ac d concentration individually favor more rapid reaction, and within the time limitations of commercial apparatus more complete conversion. lhere are, however, practical limits to the extent to which these two factors may be increased either singly or in combination, for too high an acid concentration and/or temperature results in excessive polymerization of propylene which material is thereby lost to the sulphation reaction. For this reason relatively low temperatures and artificial refrigeration have been necessary when employing concentrated sulphuric acid. Gonversely, even at normal temperatures it has been necessary to employ a strength of acid which results in considerable polymerization and loss of propylene,

We have ifound, however, that we are enabled to operate satisfactorily with a lower combination of acid concentration and temperature by suitable control of the partial ressure of the propylene. The pressure reierred to is independent of the gross or total pressure or the materials present and is the actual pressure exerted by the proportion of propylene present. It is frequently necessary to' carry out the sulphation in gas phase, particularly where the raw material contains a minor proportion of propylene. Even in this case, however, by adjustment of the partial pressure of the propylene present uniform sulphating conditions may he PROCESS FOR SULPHA'IING OLEFINES Application filed December 10, 1930. Serial No. 501,469.

obtained compatible with the employment of an acid concentration and temperature in combination at which highly satisfactory reaction velocities and conversion yields result, together with a very substantial inhibition of the usual polymerization loss. In general, we operate with propylene partial pressures in excess'of 50 pounds gage to the square inch. Generally speahin ,with these partial pressures we may emp oy acid of 70 to 80%, H 80, content, at temperatures of from to 40 C. centrations and temperatures recited are coextensive throughout the entire range, via the higher acid concentration may if desired be employed in combination with a higher temperature and vice versa, for best results we prefer to employ an acid concentration of from 75 to 80% at a temperature of from 10 to 0., and an acid concentration o1? from T0 to 75% at a temperature of from 25 to C. Better results may be obtained by the employment of partial pressures in er.- cess of 100 pounds per square inch. With either partial pressurehowever, when the acid concentration and temperature are fixed uniform sulphation may be obtained regard less of the amount of diluent gases which may be present.

it is a further advantage or the prescribed control of the partial pressure or the propylene that it is thereby rendered possible in a single stage reaction to form dipropyl eul phate by contacting the propylene with aqueous sulphuric acid. 'lhc'dipropyl sulphate is intrinsically valuable as an intermediate in chemical reactions and as a source material for the generation of pure iso ropyl alcohol oat-exceptional high quality. or the generation of the dipropyl sulphate it is necessary to maintain a partial pressure in excess of pounds to the square inch and to maintain the sulphuric acid and propylene in contact until the acid has been converted at least in part into dipro yl sulphate. Par- While the acid con-' tial pressures in excess or 100 pounds to the square inch fayor the conversion. For this purpose acid concentrations of from to may be employed at temperatures ranging from 10 to 45 C. The dipropyl sulphate Edit generated is an oily material only limitedly soluble in the solution of sulphuric acid or mono propyl sulphate. It may be so arated therefrom by stratification and therea ter hydrolyzedby digesting or distilling the same of water to produce isopropyl alcohol. Alternatively, the hydrolysis of the dipropyl sulphate may be accom lished in the dpresence of the aqueous sulp uric acid by a ding water followed by digestion or distillation. It is articularly desirable, preliminary to the su phation of the propylene, to remove either y chemical or physical means substantially all the olefines of more than 3 carbon atoms to the molecule. This results in an improved sulphating eificiency where the effort is to ma e either mono or dipropyl sulphate, but is particularly helpful where the effort is to generate the dipro yl sulphate as it avoids contaminating t e ipropyl sulphate with polymers which complicate the recovery of isopropyl alcohol and further tend to impart an undesirable odor t0 the finished material.

The generation of the dipropyl sulphate may be carried out with propylene wh1ch is either in liquid or gas phase. The preferred procedure or this pur ose consists in se arating from the cracke materials a fraction the olefine content of which consists predominantly of olefines of 3 carbon atoms to the molecule. For every stipulated artial pressure of propylene this eflects a re notion in the tota pressure required with corresponding economies in constructing and/or operating the equipment. These economies and the chemical efliciency of the operation are further enhanced by the employment of a highly cracked raw material which yields a hydrocarbon fraction consisting predominantly of olefines of 3 carbon atoms to the molecule. -In our preferred procedure the raw material is the normally gaseous olefines produced by cracking mineral oil in vapor phase at temperatures between 1000 and 1200 F., preferably between 1050 and 1150 F. From this raw material we separate by distillation specifically rectification, a h drocarbon fraction consisting predominant y of olefines of 3 carbon atoms to the molecule. In actual practice this fraction contains only minor proportions of olefines of more or less than 3 carbon atoms to the molecule and will ordinarily contain not less than of propylene.

As a specific exam le of the application of our rocess, such a raction was agitated at 25 with an aqueous solution of sulphuric acid containing 80%, H 80 The partial pressure of the prop lane was about pounds per square inc When a quantity of gas corresponding to 2 mole of propyleneto one of sulphuric acid had been added, the introduction of ropylene was discontinued and the agitatlon was thereafter continued for about one hour. The reaction was thereafter diluted with about six volumes of water, whereupon di-isopropyl sulphate separated as a ark colored 011 very armgly soluble in the aqueous la er. When t e diluted material was warme and a 'tated, the drisopropyl sulphate hydrolyze rapidly and substantially pure isopropyl sulphate was separated by distillation.

In practice it may not be desirable under all conditions to attempt to generate the-theoretical quantities of dlpropyl sulphate based on the acid taken as the reaction velocity diminishes as this condition is approached. The major part of the acid may, owever, be con-. veniently converted at avorable reaction velocities to dipropyl sulphate. Some dipropyl sul hate is formed under the conditions outline even where two mole of acid are present for each mol of ropylene, but the proportion of dipro yl su phate produced is favored by the emp oyment of less than two mole of acid for each mol of prop lene. Somewhat less than three-halfs mols 0 acid for each mol of propylene is favored in commercial practice.

Where the propylene is treated in gas phase the sulphation reaction is preferably carried out in a column of the bubb e tower type preferably equipped with plates, bell-caps and downflow pipes so as to maintain the continuous counter-current contact of the gas and acid. We find that the bubble tower t of contactor is highly preferable to t e packed tower, inasmuch as it permits the maintenance of a definite volume of acid in the tower at all times and thereby enables us to maintain an desired rate of flow of acid and as wh' e simultaneously permitt1n comp ete control of the time durin which the materials are in contact. The co umn should, of course, be suitably equi ped to operate at the pressures required, and superior results are obtainable in consequence of the complete control of the concentrations and volumes of acid and of the simultaneous volumes and concentrations of ethylene which are made possible by carrying out the reaction within the range of pressures hereinbefore specified.

The foregoing specific description is for purposes of illustration and not of limitation. It is therefore our intention that the invention be limited only by the appended claims .or their equivalents in which we have ondeavored to claim broadly all inherent novelty.

We claim 1. Process of'sulphating propylene, which pressure of said propylene at not less than pounds gage per square inch.

2. Process according to claim 1, carried out at a partial pressure of prop lene not less than 100 pounds per square inch 3. Process of sulphating propylene, which comprises contacting same in gas phase with aqueous sulphuric acid of from 65 to 80%, H SO content, at a temperature of from 10 to 40 0., while maintaining the partial pressure of said propylene in excess of 50 pounds gage per square inch.

4. Process according to claim 3, in which the partial pressure of the propylene is maintained at not less than 100 pounds gage per square inch.

5. Process of sulphating propylene, which comprises contacting same under pressure with aqueous sulphuric acid of from 65 to 85%, H SO content, while maintaining the partial pressure of said propylene 'at not less than 50 pounds gage per square inch, main taining a temperature at which sulphation of propylene takes place, and maintaining such contact until the acid is at least in part converted into dipropyl sul hate.

6. Process according to c aim 5, in which the partial pressure of the propylene is maintained at not less than 100 pounds gage per square inch.

7. Process of sulphating propylene, hich comprises contacting same under pr sure with aqueous sulphuric acid of from to 85%, H content, at a temperature of 4 from 10 to 40 C., while maintaining the partial pressure of said propylene at not less 

